1. Field of the Invention
Embodiments of the invention relate generally to substrates for semiconductor packages. More particularly, embodiments of the invention relate to substrates capable of significantly reducing electromagnetic interference (EMI).
A claim of priority is made to Korean Patent Application No. 10-2006-0053114, filed on Jun. 13, 2006, the disclosure of which is hereby incorporated by reference in its entirety.
2. Description of Related Art
In recent years, electronic devices such as mobile information terminals, cellular telephones, liquid crystal display panels, and notebook computers have continued to get smaller, thinner, and lighter. At the same time, the size and performance of various components within these electronic devices have been adjusted accordingly. For example, semiconductor devices within the electronic devices have become smaller, lighter, and increasingly integrated.
As these electronic devices have become thinner, smaller, and more dense, the use of tape wiring substrates has become increasingly common in the field of semiconductor chip mounting technology. Tape wiring substrates typically have a structure in which a wiring pattern layer and leads connected thereto are formed on a thin film of insulating material such as polyimide resin.
Unfortunately, these electronic devices tend to generate electromagnetic waves that can cause disruptions in other electronic devices, and in some cases, can even be harmful to human bodies. In view of these potential problems, governments and other public institutions have developed regulations to govern so-called “electromagnetic interference” (EMI) caused by the emission of electromagnetic waves by electronic devices.
Typically, the term “EMI” is used to refer to undesired interactions between high-frequency noise generated by electronic circuits or systems and neighboring circuits, systems, or human bodies. In many countries, products are required to pass tests to verify that they meet prescribed EMI emission standards before they can be released to the public.
One conventional approach to regulating the amount of EMI emitted by an electronic device is to form a flat conductor on a printed circuit board within the device, wherein the flat conductor is connected between one or more circuits and ground. The purpose of the flat conductor is to shunt at least some of the emitted EMI to ground to prevent the EMI from adversely affecting the device's surroundings.
Unfortunately, however, this conventional approach may fail to sufficiently reduce the EMI and could benefit from enhancement in several aspects.